1. Field of Invention
The invention relates to a multi-light driving device, an LCD and a method for driving the LCD and, in particular, to a multi-light driving device, an LCD and a method for driving the LCD, which generate a dark zone that is shifted in sequence on a screen of the LCD.
2. Related Art
Liquid crystal displays, (LCDs) are widely spread in electrical products such as computers. Accompanying the developing of LCD technology, the qualities of LCDs are improved and the screen sizes of LCDs are increased. Thus, the LCD is suitable for a TV display, which usually plays moving picture images. The LCD, however, has poor response time for the moving picture images, and, to make it worse, human eyes have the persistence of vision. Therefore, some problems, such as image blurring, exist when using an LCD for the TV display. Thus, the LCD is inferior to the conventional TV displays, which do not have the above-mentioned problem, and has limited applications for serving as a TV display.
The conventional TV displays usually employ a cathode ray tube (CRT). Since the CRT utilizes impulse-type display method to show images, the above-mentioned image blurring issue caused by persistence of vision will not occur. In contrary, the conventional LCD utilizes hold-type display method to show images, such that when showing moving picture images, the image blurring caused by the persistence of vision will easily occur in the screen of the LCD.
Recently, a blink technology is disclosed to solve the image blurring issue. The blink technology performs on/off switching of the entire light-emitting units of the backlight module of an LCD, so that the backlight module can create blinking effect. Thus, the backlight module of the LCD can simulate the impulse-type display for eliminating the image blurring issue. Regarding the blink technology, since the light-emitting units perform on/off switching all the time, the brightness changing of the LCD screen is huge. This may result in flicker issue of vision. In addition, when the light-emitting units perform or/off switching all the time, the effective brightness of the whole screen is decreased and the quality of the display suffers. Moreover, when the light-emitting unit is turned on after just being turned off, the current of the light-emitting unit, which is typically a lamp, is fast changing and will pass through a transient period. When the current of the lamp passes through the transient, the current and the brightness of the lamp may not be accurately controlled, and thus the brightness uniformity between the lamps may not be easily maintained.
As mentioned above, it is an important subjective to provide an LCD and a method for driving the LCD, which can maintain the brightness of the LCD, eliminate the image blurring, and prevent the flicker issue. Furthermore, it is an addition important subjective to provide a multi-light driving device, which can maintain the brightness of an LCD, eliminate the image blurring, and prevent the flicker issue.